Dual hub for reels



May 30, 1967 F. DEKKER 3,322,364

DUAL HUB FOR REELS Filed March l5, 1965 5 Sheets-Sheet l E www May 30, 1967 F. DEKKER DUAL HUB FOR REELS 5 Sheets-Sheet 2 Filed March l5, 1965 3 Sheets- Smet 3 F' DEKKER RII? I DUAL HUB FOR REELS May 30, 1967 Filed March l5, 1965 Vlllfrli United States Patent 3,322,354 Patented May 30, 1967 3,322,364 DUAL HUB FOR REELS Frank Dekker, lngiewood, Calif., assigner t Minnesota Mining and lllanufacturing Company, St. liaul, Minn., a corporation of Delaware Filed Mar. 15, 196s, ser. N0. senses I8 Claims. (Cl. 242-68.3)

This invention relates to tape transport systems and more particular-ly refers to a dual hub assembly for mounting two tape reels coaxially in closely spaced relationship in a tape transport system, each reel having an axial opening to receive the hub assembly.

Many occasions arise for using two recording tape systems cooperatively. One example is the use of two magnetic recording tapes in tandem for recording signals continuously through a period of recording signals or a period of reproducing signals, which period is beyond the capacity afforded yby the length of a single tape. Recording or reproducing signals is started on one tape and as the tape nears the end of its run the recording or reproducing of signals is transferred toy the second tape. Another example is the common use of one tape to reproduce signals that are recorded on a second tape with both tapes running simultaneously. Still another example is the use of one tape to record signals with the other tape standing by for use in the event of failure of the operation of the rst tape.

In all of these instances, two systems in two separate cabinets it is highly desirable for a munber of reasons to combine the two tape transport systems in a single piece of apparatus. It has -been found that such a dual tape apparatus can be fabricated in compact form with savings in cost as well as savings in space if the reels for the two tapes are positioned coaxially on two c-losely spaced parallel decks or planes of operation. Such a coaxial double deck tape system occupies only slightly more space than a conventional single tape transport apparatus and costs only half again as much instead of twice as much.

The present invention serves this purpose by providing a double deck or dual hub assembly for mounting two reels coaxially for independent operation, one such dual hub assembly being required for two reels Vat corresponding ends of two tapes and a second dual hub being required for the two reels at the other corresponding ends of the two tapes. A dual hub assembly of this character comprises an axially inward hub structure to mount an inner reel and an axially outward hub structure to mount separate tape transport may be employed but an outer reel. Certain problems arise in the construction of such a dual hub assembly.

One problem is to construct the outer hub structure of the hub assembly to retain the outer reel but also, when desired, to permit the inner reel tol pass over the outer hub structure. This problem is met by providing the outer hub structure with a radially projecting portion to support the outer reel, the radially projecting portion being retractable to permit the inner reel to pass.

When each of the two coaxial hub structures is in operation it must firmly engage the corresponding reel and positively prevent axial withdrawal or slippage of the reel. For this purpose, spring loaded cam-actuated engagement means is incorporated in each of the two hub structures for radial expansion into engagement with the inner circumferential surface of the axial opening of the corresponding reel. The problem is to provide such an engagement means that may be manually released when only the outer end of the hub structure is accessible for manipulation.

This problem is met by making each of the two structures of the dual hub assembly longitudinally contractible and by making the engagement means of each hub structure releasable in response to axial contraction of the hub structure. In this regard a feature of t-he invention is that the inner of the two hub structures of the dual hub assembly is axially contractible in response to axial contraction of the outer hub structure. In the preferred practice of the invention the outer hub structure has an initial range of axial contraction which releases its own engagement means and has a further range of axial contraction which is transmitted to the inner hub structure to release the engagement means of the inner hub structure.

The features and advantages of the invention may be understood from the following detailed description and the accompanying drawings.

In the drawings which are to be regarded as merely illustrative:

FIG. l is a plan View of a dual hub assembly embodying the invention and mounting a pair of inner and outer reels;

FIG. 2 is a longitudinal section taken along the angular line 2-2 of FIG. l showing the engagement means of the two coaxial hub structures and also showing the retractable radial projection of the outer hub structure that supports the outer reel;

FIG. 3 is a fragmentary longitudinal section along the line 3-3 of FIG. l showing a downwardly extending pin for transmitting axial contraction movement of the outer hub structure to the inner hub structure;

FIG. 4 is a transverse section along the line 4 4 of FIG. 2 showing how lugs in the form of longitudinal pins of the inner hub structure engage corresponding grooves in the inner reel to lock the inner reel against rotation relative to the inner hub structure;

FIG. 5 is a fragmentary longitudinal section along the line 5-5 of FIG. 4 showing one of the longitudinal pins;

FIG. 6 is a diametrical section along the line 6 6 of FIG. 1 showing how the pin of FIG. 3 is positioned to act on the inner hub structure;

FIG. 7 is a view similar to FIG. 6 showing the outer hub structure axially contracted to a degree for release of its own engagement means without releasing the engagement means of the inner hub structure; and

FIG. 8 is a similar sectional view showing the outer hub structure axially contracted beyond the state shown in FIG. 7, the further axial contraction resulting in axial contraction of the inner hub structure to release the inner reel.

The dual hub assembly in this particular embodiment of the invention is designed to mount reels of the character shown in FIGS. 1 and 2. Each of the reels 19 is of a well known construction with a circular axial opening l2 having an inner circumferential surface with three longitudinal grooves 15 at equal circumferential spacing.

The dual hub assembly comprises a radially inner hub structure, generally designated l5 mounted on the upper end of a tubular shaft 18 and an outer coaxial hub structure, generally designated 2i), mounted on the upper end of an inner concentric shaft 22. The inner hub structure 16 is secured -on the tubular shaft 18 by at least one set screw 24 and the outer hub assembly 20 is secured on the shaft 22 by at least one set screw 25, the two shafts being maintained in coaxial alignment by a pair of spaced ball bearings 26 inside the inner hub assembly.

Each of the two coaxial hub assemblies 16 and 20 is constructed for axial extension and contraction and for this purpose each hub structure is made in two sections. Thus the inner hub structure 16 comprises an axially fixed inner member 28 and an axially movable outer member 30, and in like manner the outer hub structure 20 comprises an axially fixed inner member 32 and an axially mova-ble outer member 34, the two cooperating members of each hub structure being in sliding engagement with each other.

The fixed inner member 28 of the inner hub structure 16 is Iformed with a short circumferential wall 35 that is dimensioned to fit into the axial opening 12 of a reel l@ and is provided with a circumscribing O-ring 36 for snug fit in the axial opening. The fixed inner member 28 is further provided with a radially projecting portion in the form of a radial flange 38 for supporting abutment against the inner face of a reel 1i). Three short longitudinal pins 39 equally circumferentially spaced on the radial flange 33 serve to engage the inner longitudinal grooves l5 of a reel as best shown in FIG. 5 to prevent rotation of the reel relative to the inner member 28. The axially xed inner member 28 is further formed with a relatively long cylindrical inner wall lli which lcarries a collar in the form of a conical cam d2, the collar resting against a shoulder of the inner circumferential wall and being retained by a snap ring 44.

The outer member 30 of the inner hub assembly 16 is in the form of a cylinder that is open at both ends7 the inner end of the cylinder being reduced in diameter to form a cylindrical skirt l5 which slidingly telescopes inside the circumferential wall 3-5 of the inner fixed member 28. Thus the circumferential wall of the axially fixed inner member 23 serves as a guide for the axial movements of the outer member 3Q.

The axia ly movable outer member 3? is provided with three radial apertures 48 at equal circumferential spacing to house three engagement means in thc form of three metal -balls Sti, the outer ends of the apertures being restricted to keep the balls captive in the absence of a reel 10. A suitable coil spring 54 acting in compression between the axially fixed inner member 2S and a snap ring 55 on the outer member 3f) continuously urges the outer member axially outward from the inner member.

If a reel lil is mouned on the inner hub structure le as shown in FIG. 2, the outward spring pressure against the outer member 3@ results in wedging of the three metal balls 50 between the conical cam 42 and the inner circumferential surface of the reel to lock the reel on the hu'b structure in a manner to prevent withdrawal of the reel from the radial flange 33. The reel may be unlocked or released simply by contracting the inner hub structure 16 by manual force applied axially against the outer member 30, the resultant axial movement of the outer member shifting the three metal balls 5d away from the conical cam 42. In the absence of a reel l@ on the lower hub structure, the lower hub structure is axially expanded further to a limit position at which the three metal balls 5l) are displaced outward to their limits in the radial apertures 4S.

The outer hub structure Ztl is largely similar in construction to the inner hub member le as indicated by the use of corresponding numerals to indicate corresponding parts. Thus the outer hub structure 2t) lik-e the inner hub structure l5 provides three metal balls 5t) to cooperate in the previously described manner with a conical cam d2 under the pressure of a compressed coil spring 54.

The outer hub structure 2@ differs from the inner hub structure le in being provided with a radial portion to support a reel with the radial portion retractable to permit a reel to pass over the outer hub structure 2li. In this embodiment of this invention the radially projecting portion of the outer hub structure comprises three radial pins 58 slidingly mounted in three corresponding radial bores 60 in the circumferential wall 35 of the axially fixed inner member 32.

Any suitable means may be provided to control the radial extension and contraction of the three pins 5S. ln this construction, each of the three radial pins 5S is urged radially inward by a surrounding coil spring 62 that acts in compression between the circumferential wall 35 and a snap ring 64 on the pin. The three radial pins 58 are controlled by a manually operable axial plunger 65 that is mounted in the outer end of the outer hub structure Ztl, the plunger having an exterior operating knob as shown. The plunger 65 is slidingly mounted in a guide aperture 68 in an outer end wall 7i) of the outer member 34 and is provided with a circumscribing snap ring 72 which serves as a stop in cooperation with the end wall to limit the axially outward movement of the plunger. The inner end of the plunger 65 is formed with a rounded or chamfered nose as shown and is further formed with a circumferential groove 7d for cooperation with the three radial pins 58.

When a reel l@ is mounted on the outer hub structure yZtl as shown in FIG. 2, the plunger 65 is in its normal inner position at which it holds the three pins 5S in their effective outer positions, the rounded inner ends of the three pins seating in the circumferential groove 74- of the plunger. When the plunger 65 is manually retracted as shown in FIG. 8 out of the region of the three pins 58, the three pins are retracted axially inward by their individual coil springs 62. When the plunger e5 is subsequently restored to its normal position the rounded or chamfered nose of the plunger spreads the three pins 58 apart to restore the three pins to their effective positions.

As heretofore stated a feature of the invention is the concept of causin-g the inner hub structure i6 to contract in response to contraction of the outer hub structure 2li. For this purpose an operating pin 75 which is best shown in FlG. 3 (and also shown in FIG. 6) is `fixedly mounted on the lower rim of the outer member .34 of the outer hub structure Ztl and extends through a longitudinal bore 76 in the axially fixed member 32. `When the two hub structures L16 and 2@ engage coresponding reels, the pin 75 is sufficiently retracted to avoid interference with axial exparisien to the limit of the inner hub structure 16, theV retracted position of the pin being shown in FIG. 7. When manual pressure is applied to the outer end of the outer member 34 of the outer hub structure 2@ to contract the outer hub structure, the outer hub structure contracts sufficiently to relax its three metal balls 5l) for release of the outer reel l@ as shown in FIG. 7, the three balls of the outer structure being relaxed before the pin 75 advances sufficiently to contract the inner hub assembly 2i). Additional inward contraction to the limit of the outer hub assembly 2li as shown in FIG. 8, advances the pin 75 sufiiciently to contract the inner hub assembly 16 and thereby relax the three balls 5@ of the inner hub assembly to release the reel on the inner assembly.

As heretofore stated three longitudinal pins 39 on the inner Ahub structure le engages the three longitudinal grooves of a reel to key the reel to the inner hub structure to prevent relative rotation of the reel. For the same purpose, the outer hub structure 2? is provided with three radial means in the form of three short longitudinal ribs 78 (FIGS. 1 and 3) on the periphery of the inner member 32 to engage the longitudinal grooves l5 of a reel on the outer hub structure. Preferably the three ribs 78 are in longitudinal alignment with the three pins 39.

The manner in which the dual hub assembly functions for its purpose may be readily understood from the foregoing description. In preparation for mounting a reel 10 on the inner hub structure le, the knob d6 is manipulated to retract the plunger 65 as shown in FIG. 8 to permit the three springs 62 to retract the three radial pins 58 out of the outer hub structure 2li. With the three pins 58 out of the way, a reel l@ is placed on the outer hub structure 2@ with the three longitudinal grooves l5 of the reel in axial alignment with the three 4ribs '73 and then the reel is moved past the outer hub structure onto the inner hub structure 16, the three longitudinal grooves of the reel passing freely over the three longitudinal ribs onto the three pins 39?. If desired manual pressure may be applied to the outer end wall 70 of the outer hub structure 2@ to contract both hub structures suiciently to relax both sets of the metal balls 50 to permit the reel to pass freely to its desired alternate position against the radial flange 38 of the inner hub structure.

It is not necessary, however, to apply force to the end wall 70 for this purpose because the two hub assemblies will be contracted in turn by abutment of the reel against the two sets of metal balls Stb in sequence. Thus when the reel encounters the protruding metal balls 50 of the expanded outer hub assembly 2.0, the axially moving reel acting against the protruding balls forces sucient axial contraction of the outer hub structure to relax the balls to permit the reel to pass completely over the outer hub structure. Subsequently the reel encounters the protruding metal balls Sti of the inner hub structure 16 and thereby contracts the `inner hub structure axially to relax the balls and permit the reel to reach its final position against the radial flange 33. It is apparent, then, that with the knob 66 retracted, a reel 1t) may be mounted on the inner hub structure I6 by simply forcing the reel axially over the two hub structures in one movement Vuntil the reel encounters the radial flange 38 of the inner hub structure. The reel is then automatically llocked in place by the three metal balls 5l) of the inner hub assembly.

After a reel is mounted on the inner hub stmcture 16 in this manner, the knob 66 is depressed to restore the radial pins S3 to their outer effective positions and then a second reel is telescoped over the ribs '7S of the outer hub structure Ztl against the three radial pins 58. Here again, manual force may be applied to the outer end wall '70 of the outer hub structure 20 for the purpose of relaxing the corresponding metal balls but if desired the reel may be simply forced against the protruding metal balls 5t) to cause sutiicient contraction of the outer hub structure to relax the balls.

To remove the two reels from the dual hub assembly, first the outer hub assembly 2u is contracted by manual pressure against the end wall '7th sutiiciently to relax the corresponding three metal balls Sti to permit the outer reel to be withdrawn. The knob 66 is then pulled to its outer position shown in FIG. S to retract the three radial pins 53. Manual pressure is again applied to the end wall 70 of the outer hub structure 2@ suciently to contract the inner hub structure 16 to relax the three metal balls of the inner hub structure to release the inner reel for withdrawal. As the inner reel is withdrawn and passes over the outer hub structure 2t? the three longitudinal grooves of the reel ride over the three longitudinal ribs 78 of the outer hub structure.

My description in speciiic detail of the selected embodiment of the invention will suggest various changes, substitutions and other departures-from my disclosure within the spirit and scope of the appended claims.

I claim:

1. yIn an apparatus for rotatably mounting two closely spaced coaxial reels having axial openings with longitudinal grooves therein, the combination of:

closely spaced inner and outer axially aligned hub structures to mount an inner reel and an outer reel respectively;

radially extending support means on the two hub structures respectively to abut the inner faces of the two reels respectively, and

the support means on the outer huh structure being radially retractable to permit the inner reel to pass over the outer hub structure.

2. In an apparatus for rotatably mounting two closely spaced coaxial reels having axial openings with longitudinal grooves therein, the combination of:

closely spaced inner and outer axially aligned hub structures to mount an inner reel and an outer reel respectively;

radially extending support means on the two hub structures respectively lto abut the inner faces of the two reels respectively,

the support means on the outer hub structure being radially retractable to permit the inner reel to pass over the outer hub structure; and

means on the two hub structures respectively to releasably engage the two reels respectively to hold the two reels against retraction from the two corresponding support means.

3. A combination as set forth in claim 2 which includes means on the outer end of the outer hub structure that is manually operable to release the two engaging means on the two hub structures.

4. A combination as set forth in claim 3 in which said i manually operable means has a tirst range of operation to release the engaging means in the outer hub structure and a second range of operation to release the engaging means on the inner hub structure.

5. In an apparatus for mounting two'closely spaced coaxial inner and outer reels respectively which reels have axial openings with inner longitudinal grooves therein, the combination of:

a rst tubular shaft;

an axially inner hub structure mounted on the tubular shaft and having a concentric portion to it into the axial opening of the inner reel;

radially projecting support means on the inner hub structure to abut the inner face of the inner reel; means on the inner hub structure to engage at least one longitudinal groove of Ithe inner reel to prevent rotation of the inner reel relative to the inner hub structure; iirst engaging means on the inner' hub structure to releasably engage the inner reel inside the aperture thereof to hold the inner reel against axial retraction from the support means;

a second inner shaft extending through the tubular shaft coaxially thereof;

an axially outer hub structure to tit into the axial opening of the outer reel, the outer hub structure being on the second inner shaft adjacent the inner hub structure;

second radially projecting support means on the outer hub structure to abut the inner face of the outer reel,

said second support means being radially retractable to clear the axial opening of the inner reel to permit the inner reel to pass axially over the outer hub structure; and

second engaging means on the outer hub structure to releasably engage the outer reel to hold the outer reel against axial retraction from the second support means.

6, A combination as set forth in claim 5 which includes means on the Vouter end of the outer hub structure to release both of said engaging means.

7. A combination as set forth in claim 5 which includes means on the outer end of the outer hub structure to retract the second support means.

8. In an apparatus to mount an inner reel and an outer reel coaxially, each reel having an axial opening, the combination of:

an axially inner hub structure to carry the inner reel and an axially outer hub structure coaxially thereof to carry the outer reel, each of the two hub structures being dimensioned to telescope into the axial opening of a reel and having a radially projecting portion to abut the inner face of the reel,

each hub structure being axially expansible from a contracted state to a limit of axial expansion and being biased to expand to its limit; and

engagement means carried by each of the two structures tor protrude therefrom into engagement with a reel in response to axial extension of the hub structure,

to make operating contact with the inner hub structure after the outer hub structure is contracted to the point of releasing the engagement means of the outer hub structure.

17. In a rotary device for releasably mounting a reel that has an axial opening therein, the combination of:

an axially inner rotary member xed against axial movement, the inner member having a radial projecting portion to abut vthe inner face of the reel; an axially outer member in sliding engagement with the inner member for axial movement relative to the inner member; spring means acting between the two members to urge the outer member axially outward from the inner member, the two members constituting an axially extensible and contractible hub structure -dimensioned to telescope into the axial opening of the reel; stop means to limit relative outward movement of the outer member thereby to limit axial extension of the hub structure; and engagement means carried by one of the two members of the hub structure to protrude radially outward therefrom against the inner surface of the axial opening of the reel in response to axial extension of the hub structure, thereby to hold the reel against axially against axially outward movement away from the projection portion of the inner member,

said engagement means relaxing in response to axial contraction ofthe hub structure,

whereby the reel may be telescoped over the hub structure by manual force to encounter the protruding engagement means and thereby -retract the outer member towards the inner mem-ber in opposition to the spring means to relax the engagement means to permit the reel to move into position against the projecting portion of the inner member and whereby relaxing the manual force permits radial extension of the hub structure by the spring means to cause the engagement means to protrude into engagement with the reel to hold the reel against axial movement away from the projecting portion of the inner member.

18, A combination as set forth in claim 17 in which the engagement means is carried `by the outer member.

References Cited UNITED STATES PATENTS 5/1955 Bunch 242-683 3,124,319 3/1964 Cohen 242-68.3

FRANK l. COHEN, Primary Examiner.

Assistant Examiners. 

1. IN AN APPARATUS FOR ROTATABLY MOUNTING TWO CLOSELY SPACED COAXIAL REELS HAVING AXIAL OPENINGS WITH LONGITUDINAL GROOVED THEREIN, THE COMBINATION OF: CLOSELY SPACED INNER AND OUTER AXIALLY ALIGNED HUB STRUCTURES TO MOUNT AN INNER REEL AND AN OUTER REEL RESPECTIVELY; RADIALLY EXTENDING SUPPORT MEANS ON THE TWO HUB STRUCTURES RESPECTIVELY TO ABUT THE INNER FACES OF THE TWO REELS RESPECTIVELY, AND 